Resealable push-pull closures (or as they are sometimes called, “sports closures”) allow a person to pour out a container's contents without the need to fully remove the closure from the container.
Such closures typically comprise a main cap that seals the container in the manner of normal closures as known in the art. The top surface of the main cap normally has an opening in fluid communication with the bore of a spout. The spout in turn has a plug member that partially blocks the bore. To seal the container, a top cap, which also has an aperture, is mounted to the spout. The top cap is normally movable between at least a first position in which its aperture is sealed by the plug member so sealing the container and a second position in which the aperture is not sealed by the plug member so allowing the container's contents to exit from the container around the plug member and through the aperture of the top cap.
The top cap is generally mounted to the spout in a manner such that it is readily movable between the first and second positions by only one hand or even by the teeth. This traditionally has made the closure popular with sportspersons, such as runners or cyclists, who may wish to consume a product but who may only have one hand free whilst participating in their sport.
The use of such a closure is, however, not restricted only to containers for sports drinks and they have found application in an ever wider range of container types and products in general use by consumers. For example, the closures have been used to seal containers containing beverages marketed at children. The closures are often easier to unseal than the traditional requirement of fully unscrewing a closure from the container. The smaller opening in the top cap also restricts the rate of flow of the beverage from the container making it easier for a child to consume the beverage without mess.
Containers for carbonated beverages must be sealed by closures that can withstand the increase in pressure created Within the container by the carbonation of the beverage. The closures must also retain a sufficient degree of sealing to prevent loss of gas from the container in the time between filling of the container and eventual consumption of the beverage by the consumer.
U.S. Pat. No. 5,423,444 discloses a plastic closure for a container having an externally screw threaded neck that can be used for carbonated beverages.
The closure in U.S. Pat. No. 5,423,444 has a top portion and an internally threaded skirt. An annular sealing rib also projects downwardly from the underside of the top portion. The rib includes a first substantially cylindrical portion contiguous with the underside of the top portion and lying adjacent to or abutting with the skirt, and a second, frusto-conical, portion contiguous with the end of the first portion distal to the underside of the top portion and extending radially inwardly to a circular free edge. During threaded attachment of the closure with the neck, the second, frusto-conical, portion is engaged by a free end of the neck and folded back at least towards and preferably against the first portion of the rib to form a gas tight seal between at least the outer surface of the neck of the container and the closure.
U.S. Pat. No. 5,609,263 discloses a closure having a sealing rib in which there is at the free end of the second portion of the rib a thick seal ring of substantially circular cross-sectional shape. The rib and the seal ring are dimensioned to engage the free end of the neck when the closure is threaded onto the neck such that when the neck is fully screwed into the closure its free end crushes the seal ring directly against the inside surface of the top portion of the closure.
Australian Patent Application No 80944/98 discloses still further variants of the closure described in U.S. Pat. No. 5,423,444. In one variant, the sealing rib of the closure has a third portion connected to the second portion at or adjacent its circular edge and extending generally in a direction away from the top portion. The third portion is substantially no thicker than the second portion and has a length longer than its thickness. On attachment of this closure to a container, the third portion is positioned between the neck of the container and the underside of the top portion of the closure.
International Publication No WO 00/64774 (Appl. No. PCT/AU00/00353) describes one type of resealable push-pull closure.
The present invention is directed to a modified resealable push-pull closure that is suitable for, but not limited to, sealing containers for aerated or at least partially carbonated beverages.
Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.